Ionic discharge device



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Feb. E8, Eg. C. DEPEW HAL IONIC DISCHARGE DEVICE Filed Sept. 8; 1943 2 Sheetssheet l INVENURS.'

ATTORNEY Feb. i8, w47. c. DEPEW ETAL. g@

IONIC DISCHARGE DEVICE Fied sept. s, 1943 2 sheets-sheet 2 EPEW @EPP NVNES LUCE BV 04m tf. Mme?,

TTRNEV a INVEIWURS.' J2. R5 AN.

Patented Feb. 18, 194'? i f.

IONIC DISC fil' 1"* GE DEVICE Charles Depew, Oakland, N. 3., andWae A. Depp, Elmhurst, and Alfred N. Luce, Port Washington, N. Y., and .lames R. Haynes.

Chatham, N. .ll

., assignors to Bell Telephone Laboratories, Incorporated, New York, N. if.. a corporation of -New York Application September 8, 1943, Serial No. 501,530)

(Cl. Z50-27.5)

18 Claims.

This invention relates to ionic discharge devices and more particularly to spark discharge devices operating at high voltage levels and having a stable uniform pulsing periodicity of discharge.

The principal object of the invention is to obtain a, long operating life for spark pulsing devices functioning at high current levels.

A specific object of the invention is to facilitate the stability of the vsparking discharge with a minimum of sputtering of the electrodes.

These objects are attained in accordance with the general aspects of this invention by the provision of a multiplicity of sparking gaps in a gaseous environment at a pressure more or less than atmospheric wherein the individual gaps are triggered or fired with a minimum of ionization lag and are deionized quickly to attain a high periodicity of discharge capable of being utilized for pulse modulation in high frequency signaling systems.

In accordance with specific embodiments of the invention an evacuated vessel containing a gase-l signal transmission systems.

In one arrangement the electrodes are rectangular metallic members mounted in parallel pairs intermediate electrodes are coupled together to form a composite cathanode element. charge gaps between the respective pairs of electrodes are initially ionized by the provision of a The cathanode may be a single element interposed between a cathode and anode, one side of the single element serving as an anode for the cathode of one gap, while the other side functions as the cathode opposite the anode of the other gap. formation of the outer electrodes as sections of a cylinder so that the center of the convex electrodes defines the minimum spark gap paths between the multiple electrodes.

Another embodiment of the invention comprises multiple discs arranged in parallel relation, .the intermediate discs functioning as dual cathodes and anodes while the opposite end discs serve only as cathode 'and anode, respectively. Each; disc is provided with a central recess and all of the discs except the terminal disc carries a metallic insert in the recess to form a cathode surfacein opposed relation to the rear surface of an adiacent disc which functions as the anode, they anode surface and the adjacent insert surface forming a restricted discharge gap for the striking of a spark path therebetween. Initiation of ionization of theY gap is enhanced by the provihigh voltage.

These arrangements not only attain practical importance from the standpoint of higher voltage application for the development of spark discharge generating devices, .but also increase the operating efliciency thereof by the selective control of electrode sputtering by the choice of electrode materials and the electrode relationship. Furthermore, the cooperating electrodes of the multiple spark gap devices exhibit a sharp cutcii after breakdown .of the gaps so that a large sparking current is attained and high periodicity of pulse frequency is assured.

These and other features and advantages of this invention will be more clearly set forth in the following detailed description which, together with the accompanying drawings, represent a complete disclosure of this invention.

Fig, 1 shows in perspective one embodiment of the invention with the vessel broken away to illustrate the assembly of electrodes constituting the multiple gaps for the generation of the spark discharge.

Fig. 2 is a plan View of the electrode assembly of Fig. 1 showing the relationship between the various electrodes and the establishment of the separate discharge gaps between the respective electrodes.

Fig. 3 shows a partial view of the electrode as- A feature of this construction is the embossed portion 3|,

ysuch as tungsten,

structure shown Fig. 8 illustrates in perspective a further modiiication of the invention in which the multiple spark gaps are provided by parallel disc electrodes.

Fig. 9 is a view in cross-section of one of the composite disc electrodes showing the detail assembly of the electrode, and

Fig. 10 isa plan view of Fig. 8 taken on the -line ||0 to show the mounting of the protective shield between the electrodes and the stem.

` Referring to Figs. 1, 2 and 3 of the drawings, a specific embodiment of the invention is shown which involves multiple spark gap discharge paths between closely spaced pairs of electrodes enclosed in a bulbous vessel or evacuated chamber 2B having a dished stem 2| forming a seal for the conductors of the electrodes, the conductors extending to three external terminals 22 supported on a disc base 23 adjacent the stem of the vessel. The electrode assembly of this invention comprises a plurality of pairs of closely spaced parallel cold electrodes 24, 25, 26 and 21 mounted in lcooperating relation and defining separate spark discharge gaps 28 and 29 for the generation of high current pulsing energy of high frequency for signal transmission systems. Each electrode is formed of a rectangular-shaped metallic plate, such as molybdenum, to withstand the intense heat energy expanded in the discharge, the edges thereof being beveled, as shown at 30, to increase the rigidity of the plane surface of the plate in order to prevent warping and to maintain uniform parallel relation between the respective pairs of associated electrodes. Each electrode is also prov'ded with a central elongated which defines the discharge the enclosing vessel being removed.v

area of the electrodes within the'gap between each pair of electrodes to limit or concentrate the discharge to a definite path of controlled intensity. Alternate electrodes of the two pairs, such as 24 and 26, are provided with a superimposed layer or plate 32 of highly refractory metal,

mounted on the embossed central portion, to constitute the negative electrode or cathode surface in the discharge gap while the opposed embossed surface functions as the positive or anode surface of the discharge gap. The lateral space relation between the` plate 32 and the raised surface 3| of the anode should be restricted to a limited path not materially greater than .1 inch although it is preferable to maintain the gap at a distance of .075 inch. The choice of electrode materials, their relationship and configuration together with the adherence to uniform spacing and the combination of gaseous constituents in the ionization media insure the production of a highly intense spark discharge with a minimum of sputtering of the cathode surface beyond the limited area of the discharge path. Another advantage of his construction is the preservation of continuous operation over a life whereby high eiiiciency is attained. The electrodes are supported in uniform spaced relation by the provision of angle brackets 33 secured to the rear surfaces ot the electrodes in position to be -welded to a plurality of spaced conductors or supports 34 projecting from the dished stem 2| of the vessel.

The lateral electrodes of the assembly constitute a plurality of discharge gaps, the cathode 24 and the anode 25 forming one gap while the cathode 28 and .the anode 21 form the remaining gap. The intermediate pair of electrodes 25 and 26 may be joined together by a strap 35 whereby these electrodes function as a common cathanode for the respective cathode 24 and anode 21 in the multiple spark discharge paths of the device. The electrode assembly is surrounded by a gaseous ionizationmedium consisting of a gas or a mixture of gases, suchv as argon, helium, hydrogen, nitrogen, carbon dioxide and oxygen, a desirable combination being argon and hydrogen or argon and omgen. When oxygen is employed it is preferable to increase the volume of the enclosing vessel 20 to 200 cubic centimeters to insure the maintenance of suiiicient oxygen in the mixture during a long operating life, the mixture of gases being of the order of argon per cent, oxygen 20 per cent. If hydrogen or less absorbable inert gas is mixed with, argon the vessel may be of `a 'smaller size. The pressure of the gas or mixture of gases in the enclosing vessel may be from 20 centimeters to 5 atmospheres. A desirable pressure range for low voltage operation is from 50 to 76 centimeters of mercury and a more limited range should be between 60 and 67 centi- The addition of hydrogen and oxygen to the gaseous mixture reduces excessive sputtering of the electrodes in the spark discharge and tends to increase the triggering characteristics of the sparking path between the electrodes.

The initiation of conduction between the cold electrodes in the spark gaps is facilitated by the presence of ion-producing material within the vessel which may be provided by one or more spots of radium bromide or radium chloride paint 35 deposited on the side walls of the vessel adjacent the gaps between the electrodes to insure the presence of readily ionizable particles near the gaps of the electrodes. The ionization of the spark gaps is further enhanced by the provision of corona points 31 and 38 in the form of hookshaped wires supported at opposite ends of the cathanode and arranged in such a manner to direct the pointed ends of the'elements toward the center of the gaps between the respective pairs of electrodes. l These facilities in association with the spark discharge gaps materially reduce the time lag of initial conduction in thegaps whereby high efficiency may be attained in the application of the device in pulse signaling systems of high frequency and high power output. In such systems the voltage across the spark discharge device is of ahigh order, such as a direct current voltage of from 1 to 25 kilovolts, operating over a pulsing repetition rate of from to 4,000 pulses per second at a pulse length of .1 to 40 microseconds. The device of this invention facilitates pulsing periodicity under these exacting conditions with high eiliciency to achieve a high stability of operation over a long period of operating life of the electrodes and the ing discharge at high current levels of 5 to 1000 amperes and power output ratings from 1 kilolong period of 76 watt to 10.000 kilowatts.

with a minimum of sputtering production of the puls-l A modidcation oi Athe invention as shown in quent concentration of the discharge at the cen- Fig. 1 is illustrated in Figs. 4 and 5 in which the ter oi' the electrodes. This provides a more unidischarge gaps are arranged at right angles to form discharge with a minimum of time lag, the each other and the electrode assembly is more sparking discharge having a sharp cut-od due to simplified to achieve the purposes of the inventhe persistence limits in the gaps and the quenchtion. In this construction a rectangular plate 39 ing eect of the gaseous filling. The ionization is mounted upright from the stem 49 by a wire of the discharge in the gaps is enhanced by the brace 4i and is provided with a-central juxtaaddition of'radium paint 36, as shown in the posed plate d2 which is welded to the plate 39. A stem of Fig. 6, or the paint may be applied to cooperating plate 43 is mounted in parallel rela- 10 Ithe wall of the vessel as described in connection tion to the plate 39 with a limited gap therebewith Fig. 1. In addition, corona points provided tween to form the discharge path between the by angle-shaped rods Bil and 65 attached to the cathode surface d2 and the anode surface d3. A cathanode 53, which are directed toward the resimilar pair of electrodes 4t and 45 are mounted spective discharge paths between the multiple in parallel relation at right angles to the plates electrodes, readily initiate ionization in the gaps 39 and d3, the electrode M being provided with when a sparking voltage is applied to the eleca central juxtaposed activev surface 49 to contrades.

stitute the second gap in the device. The Plate Another-form of the invention is illustrated in d5 is similarly supported from the stem by a Fig. 8 in whi h a series of spark gaps is provided brace wire 41 while the intermediate electrodes 2o to attain greater power output while maintain- 43 and 4d are attached to a common conductor Ling longer life in the operation oi' the device. 48 by brace wires 49 and 59, respectively, so that In this construction each electrode is a counter- Athe electrodes d4 and 43 constitute a common part of' the other except the terminal electrode cathanode for 'the multiple discharge gaps in the so that the assembly represents a symmetrical device. In this embodiment the corona points composition for attaining high power'output with 5| and 52 project vertically from the stem and a minimum of sputtering of the electrodes. This are directed .toward the respective gaps between isv achieved through the limitation of sparking the multiple electrodes. area, interspacial relation and electrode surface A further modification of the invention is dismaterials exposed to the gaseous discharges genclosed in Figs. 6 and I7 which primarily differs 30 erated in the device.

from the previously described forms in the univ'I'he multiple spark gap electrode assembly cation of the cathanode element as a single comcomprises a plurality of similar composite disc posite electrode. Furthermore, the defining of elements 66 to 68, inclusive; and a terminal disc the limited spark gap areas is accomplished in al element 69 spaced uniformly in the vessel and diierent manner than heretofore explained. In 3r this arrangement the central electrode or cathanof the vessel, Each electrode, a ode 53 is formed of a rectangular plate orsheet 9, is formed of an aluminum disc 10 provided on of molybdenum 54 and a molybdenum or tungsten one surface with a central circular recess 1i, rod 55 is welded lengthwise to one side of the shown clearly in the terminal disc 59, Fig. 8, in sheet 5d, the combined element being mounted 40 which amolybdenum insert 12 is securely seated in the axial plane of the stem 2| by stub wires the insert being omitted from the terminal ele 56 at opposite ends attached to a pair of conducment 69. 'Ihe insert I2 forms the cathode surtors 5l in the stem. The plate 54 therefore serves face of the electrode while the rear surface of the as the anode of one gap -while the rod 55 constialuminum disc forms the anode surface. Since tutes the cathode surface of the other gap. The the successive cathode surfaces 'I2 of electrodes cooperating electrodes associated with the cath- 66 to 68 are positioned in opposed relation to the anode 53 are laterally disposed on opposite sides anode surfaces of electrodes 61 to 69 inclusive, of the common central element and are formed in a series of spark gaps is provided to carry the such a manner that the discharge is concentrated higher current output generated by the device. to a definite area in the limited sparking gaps Each electrode is uniformly spaced from the between the multiple electrodes. A rectangular adjacent electrodes to provide the required gap anode plate 58 of molybdenum is formed into a distancewhereby the discharge is restricted to section of aicylinder and diSDOSed Opposite the the path between the inseit surface 'l2 and the cathode surface of the cathanode 53. The plate plain surface of the aluminum disc directly op- 58 is supported by metaallic straps 59 placed at 55 posed thereto, the electrodes being individually opposite ends thereof and the straps are attached mounted on a pair of stub wires in the stem which to anchor wires 50 in the stem, one of the Wires are arranged in a circular boundary, as shown in being bridged by a strap 5| which is connected Fig. l0. Each electrode is provided with a pair to a leading-in conductor 51 in the stem. A of tangentially extending pins 13 which project similar arcuate sheet metal electrode 62 is mountfrom the lower peripheral surface for connection ed opposite the anode surface of the cathanode to supporting straps, such as 14, carried by elec- 53 and is provided with a Centrally welded cathtrode 66 and attached to a pair of stub wires 15 ode surface or rod 63 to establish the second in the stem, one of which forms a conductor con- `discharge gap in the device. This electrode is nected to a terminal 22 on the base 23. The suc- SuDpOrted in the Stem in the Same manner aS dea ceeding electrodes are connected to similar pairs scribed in connection with electrode 59. of straps and stub wires in the stem for mount- The configuration of the outermost electrodes ing each electrode in rigid position in relation to 58 and 62 in relation to the central cathanode 53 an adjacent, e1ectr0de. In the arrangement restricts the sparking discharge paths in the mulshown the intermediate electrodes 61 and 68 tiple gaps between the respective electrodes since function simultaneously as cathodes and anodes the limited or minimum sparking distance is conin the respective gaps while the electrodes 56 and y trolled by the closely adjacent central or mid-v 59 function only as Cathode and anode, respecportions of the electrodes. The greater distances tively. Insulation of the multiple terminal wires between the upper and lower edges of the multiple in the stem may be conveniently provided by a electrodes inhibit ionization and influence conse- Shie1d mem-ber 16, of'mica, or similar material,

having cut-out portions 11 surrounding most of theterminal wires while the shield is supported on the stem studs of electrode 61 by clips 78. A corona point rod 'I9 may be attached to a supporting brace of electrode B8 to direct the point thereof towards the gap between the composite. electrode 68 and the terminal anode 69 whereby initial ionization is produced in this gap and the succeedin gaps simultaneously break down due to the in ense ionization in the device to facilitate the handling of the high power discharge for generating frequency for which the device is adapted.

When aluminum or other easily oxidizable metal is employed as the electrode material, it is desirable to have such electrodes surrounded by an inert gas or mixture of inert gases, such as argon and helium or argon and hydrogen, whereas when highly refractory metals, such as tungsten and molybdenum, are used the gas or gaseous mixture may be any of those heretofore mentioned, it being preferable to employ a mixture of gases in view of the greatly reduced sputtering rate of the electrodes in such an environment.

While the invention has been disclosed with respect to various embodiments representing the aspects of this invention, it is, of course, understood that various modifications may be made in the detailed assembly and combination of elements as herein described without departing from the scope of the invention as defined in the appended claims.

What is claimed isz.

1. An ionic discharge device comprising an enclosing vessel containing an ionizing medium at substantial pressure, multiple parallel electrodes of similar configuration mounted within said vessel and adapted to initiate a plurality of discharges in separate uniform gaps between opposed cathode and anode surfaces, and a corona point element directed toward one of said gaps and supported in relation to the discharge path to initiate conduction therein.

2. An ionic discharge device comprising an enclosing vessel containing an ionizing medium at substantial pressure, multiple cold electrodes mounted within said vessel in cooperating relation and adapted to initiate a plurality of discharges in separate uniform gaps, each gap forming a restricted discharge path between the cathode and anode surfaces of said electrodes, each cathode surface being formed of dissimilar metals in juxtaposed relation, and multiple pointed corona electrodes within said vessel directed toward the separate gaps between the respective cathode and anode surfaces.

3. An ionic discharge device comprising an enclosing vessel containing an ionizing medium at substantial pressure, multiple cold electrodes mounted within said vessel in cooperating relation and adapted to initiate a plurality of discharges in separate uniform gaps, each gap forming a restricted discharge path between the cathode and anode surfaces of said electrodes, each cathode surface being formed of metals of different surface area and composition, the metal of higher melting point being centrally located in opposition to the adjacent anode surface and defining said restricted discharge -path in the gap, and a pointed metallic member disposed adjacent one of the gaps and directed in alignment therewith.

4. An ionic discharge device comprising an enclosing vessel containing an ionizing medium at substantial pressure. multiple parallel electhe pulse signals of high 7 said vessel and adapted to trodes of similar configuration mounted within initiate a plurality of discharges in separate uniform gaps between opposed cathode and anode surfaces, and a plurality of corona. point elements supported by an intermediate electrode and directed towardthe respective gaps between said electrodes.

5. An ionicdischarge device comprising an enclosing vessel containing an ionizing medium at substantial pressure, multiple parallel electrodes4 of similar configuration mounted within said vessel and adapted to initiate a plurality of discharges in separate uniform gaps between opposed cathode and anode surfaces, a corona point element directed toward one of said gaps and supported in relation to the discharge path to initiate conduction therein, and a transverse shield member interposed between said electrodes and the wall of said vessel. i

6. An ionic discharge device comprising an enclosing vessel containing an ionizing medium at substantial pressure, multiple parallel electrodes of similar configuration mounted within said vessel and adapted to initiate a plurality of discharges in separate uniform gaps between o pposed cathode and anode surfaces, a corona point element directed towardwone of said gaps and supported in relation to tliedischarge path to initiate conduction therein, and ionization producing material deposited on the side wall of said vessel in relation to the discharge gaps between said electrodes.

'1. An ionic discharge device comprising an enclosing vessel containing a gaseous atmosphere at substantial pressure, a pair of `parallel platelike electrodes mounted in said vessel, one of said electrodes having a layer of highly refractory metal in facing relation to the other electrode, a pair of similar electrodes interposed between the first pair but in transposed relation to the adjacent electrodes of the first pair, said second pair being tied together, and a pair of corona point electrodes attached to said second pair of electrodes and extending toward the gaps between opposed dissimilar electrodes of said first and second pairs of electrodes.

8. A multiple spark gap discharge device comprising an enclosing vessel containing a gaseous mixture substantially at atmospheric pressure, a plurality of electrodes mounted therein including a cathode surface and an anode surface and similar electrode surfaces in transposed relation opposite said cathode and anode surfaces, each pair dening a restricted discharge path therebetween, and a pair of corona point members adjacent said discharge paths, each member being directed toward a path between a respective pair of electrodes.

9. A multiple spark gap discharge device cmprising an enclosing vessel containing a gaseous mixture substantially at atmospheric pressure, a plurality of electrodes mounted therein including a cathode surface and an anode surface and similar electrode surfaces in transposed relation opposite said cathode and anode surfaces, each pair defining a restricted discharge path therebetween, a pair of corona point members adjacent said discharge paths, each member being directed toward a path between a respective pair of electrodes, and a metallic connection coupling said similar electrode surfaces together to function as a common cathanode element.

l0. A multiple spark -gap discharge device comprising an enclosing vessel containing a gaseous mixture substantially at atmospheric pressure, a

'in separate sans.

plurality of parallel electrodes mounted therein including a cathode surface and an anode surface, similar intermediate electrode surfaces in transposed relation opposite said cathode and anode surfaces, each pair dening a restricted discharge path therebetween, and a pair of corona point members adjacent said discharge paths, each member being directed toward a path between a respective pair of electrodes.

11. A high frequency spark gap discharge device comprising an enclosing vessel containing a mixture of inert gases at a pressure less than atmospheric, a cathode and an anode in spaced relation within said vessel, a cathanode interposed between said cathode and anode and forming therewith a plurality of spark discharge gaps, and a pair of corona electrodes having their points directed toward said discharge gaps.

12. A high frequency spark gap discharge device according to claim 1l in which said corona electrodes are supported by said cathanode.

13. A high frequency spark gap discharge device comprising an enclosing vessel containing a mixture of inert gases at apressure less than atmospheric, a plate-like cathode and a platelike anode mounted in perpendicular relation to each other, a cathanode positioned between said cathode and anode and forming therewith a pair of restricted discharge gaps, and a pair of corona point elements directed upwardly in line with said gaps- 14. An ionic discharge device comprising an enclosing vessel containing a mixture of argon and oxygen at a pressure of the order of 50 to 76 centimeters of mercury, a series of composite disc electrodes therein mounted in parallel relation to provide multiple spark gaps therebetween, said electrodes having a metallic body portion with a central recess on one surface, a highly refractory metallic insert seated in said recess, said insert forming a cathode surface and the body portion forming an anode surface, the insert of one disc being disposed opposite the body portion of an adjacentdisc to constitute the discharge path of the sparking energy, the distance therebetween being approximately .075 inch, a terminal electrode disc at the end of the series of electrodes, a corona point element carried by one of said composite electrodes and extending toward the adjacent gap, and a shield interposed between said electrodes and the wall of said vessel.

15. An ionic multiple spark gap discharge device comprising an enclosing vessel containing a gaseous mixture of argon and oxygen at a pressure of approximately 60 centimeters ot' mercury, a plurality of rectangular-shaped sheet metal electrodes mounted in parallel relation in vsaid vessel, each. electrode having a central raised portion to provide a sparking area between adjacent electrodes, said electrodes being mountedin pairs. to constitute opposed cathode and anode elements for the generation of a sparking discharge said cathode element'oi each pair having a highly refractory sheet metal layer superimposed on said raised portion and spaced from the anode portion a dist vice comprising an enclosing vessel containing a gaseous mixture of argon and oxygen at a pressure of approximately centimeters of mercury,

a common cathanode having a composite cathode surface and an anode surface mounted in said vessel, an anode in opposed spaced relation to said cathode surface, a composite cathode in opposed spaced relation to said anode surface, a corona point element attached to said cathanode and extending toward the gap .between one of surfaces and one of said anode surfaces, an'd another corona point element extending toward the gap between the other of said cathode and anode surfaces.

17. An ionic multiple spark gap-discharge device comprising an enclosing vessel containing a gaseous mixture of argon and oxygen at a pressure of approximately 60 centimeters of mercury,

` parallel pairs of similar-shaped rectangular metallic members disposed in uniform spaced relation to constitute'separate spark discharge gaps of limited extent, alternate members having a highly refractory central surface in opposition to the plane surface, the intermediate pair of members being connected together, and a pair of corona point elements vsupported by said intermediate pair of members and extending toward the respective gaps between said parallel pairs of members. A

18. A multiple spark gap discharge device comprising an enclosing vessel having a dished stem. a mixture of per cent oxygen and 25 per cent argon at a pressure of 67 centimeters of mercury in said vessel, two pairs of similar-shaped electrodes of sheet molybdenum mounted in collateral relation from said stem, said electrodes having embossed central portions defining the spark discharge path between each pair of electrodes, one electrode of each pair having a tungsten plate superimposed on its embossed portion in frontal relation to the embossed portion of the oppositely disposed electrode, a bridging connection between the intermediate pair of electrodes, and vertically mounted hook-shaped corona point rods carried by said intermediate pair of electrodesV and extending downwardly over the gaps between said two pairs of electrodes.

CHARLES DEPEW. WALLACE A. DEPP. 

